Hepatitis B Serology – Clinical Scenarios with Lab Data
You will be presented with 8 clinical scenarios of children with Hepatitis B serology results.
For each, interpret the serological profile and provide: 1) Diagnosis, 2) Any other test, 3) What to do next, 4) Follow-up plan.
Case 1
A 12-year-old with fatigue, jaundice, and dark urine for 5 days. No known risk factors.
HBsAg
Positive
Anti-HBs
Negative
Anti-HBc IgM
Positive
Anti-HBc IgG
Positive
HBeAg
Positive
ALT
850 U/L (elevated)
Total Bilirubin
6.5 mg/dL
1️⃣ Diagnosis: (Write your answer below)
2️⃣ Any other test: (Write your answer below)
3️⃣ What to do next: (Write your answer below)
4️⃣ Follow-up plan: (Write your answer below)
✅ Model Answer:
• Diagnosis: Acute hepatitis B infection – HBsAg positive, anti-HBc IgM positive, HBeAg positive (high infectivity).
• Any other test: HBV DNA (viral load), anti-HDV, liver function tests (INR, albumin), abdominal ultrasound.
• What to do next: Supportive care (hydration, rest, avoid hepatotoxic drugs). Monitor for fulminant hepatic failure (INR, encephalopathy). Notify public health. Evaluate household contacts.
• Follow-up plan: Check HBsAg at 6 months to determine chronicity. If HBsAg negative with anti-HBs positive → resolved. If HBsAg persists >6 months → chronic HBV, refer to hepatology.
Case 2
A 7-year-old with chronic hepatitis B (known carrier) presents for routine follow-up. ALT is normal, HBV DNA is low.
HBsAg
Positive
Anti-HBs
Negative
Anti-HBc Total
Positive
Anti-HBc IgM
Negative
HBeAg
Negative
Anti-HBe
Positive
HBV DNA
200 IU/mL (low)
ALT
25 U/L (normal)
1️⃣ Diagnosis: (Write your answer below)
2️⃣ Any other test: (Write your answer below)
3️⃣ What to do next: (Write your answer below)
4️⃣ Follow-up plan: (Write your answer below)
✅ Model Answer:
• Diagnosis: Inactive chronic hepatitis B carrier state – HBsAg positive >6 months, HBeAg negative/anti-HBe positive, low HBV DNA, normal ALT.
• Any other test: Liver stiffness measurement (FibroScan or elastography), serum alpha-fetoprotein (AFP), renal function, and bone profile (if considering future therapy).
• What to do next: No antiviral treatment indicated (immune inactive phase). Monitor for reactivation.
• Follow-up plan: Monitor ALT and HBV DNA every 6-12 months. If ALT rises or HBV DNA increases, reassess for immune active phase. Lifelong surveillance for hepatocellular carcinoma (AFP + ultrasound every 6 months if cirrhosis, otherwise based on risk).
Case 3
A 10-year-old with elevated ALT (150 U/L) and HBV DNA 2,500,000 IU/mL. HBeAg positive.
HBsAg
Positive
Anti-HBs
Negative
Anti-HBc Total
Positive
Anti-HBc IgM
Negative
HBeAg
Positive
Anti-HBe
Negative
HBV DNA
2,500,000 IU/mL (elevated)
ALT
150 U/L (elevated)
FibroScan
8.5 kPa (F2 fibrosis)
1️⃣ Diagnosis: (Write your answer below)
2️⃣ Any other test: (Write your answer below)
3️⃣ What to do next: (Write your answer below)
4️⃣ Follow-up plan: (Write your answer below)
✅ Model Answer:
• Diagnosis: Immune active chronic hepatitis B – HBeAg positive, high HBV DNA, elevated ALT, fibrosis (F2).
• Any other test: HIV/HCV/HDV screening, renal function, bone density (tenofovir), TSH, liver synthetic function (INR, albumin).
• What to do next: Start antiviral therapy: tenofovir (8-12 mg/kg/day, max 300 mg) or entecavir (0.015 mg/kg/day, max 0.5 mg). Peginterferon is alternative (age ≥1 year).
• Follow-up plan: Monitor ALT, HBV DNA every 3-6 months. Check HBeAg seroconversion (to anti-HBe). Renal function and bone density annually. Lifelong therapy usually required. HCC surveillance if cirrhosis.
Case 4
A 15-year-old who completed hepatitis B vaccine series as an infant. Anti-HBs is 8 mIU/mL (low).
HBsAg
Negative
Anti-HBs
8 mIU/mL (low, <10)
Anti-HBc Total
Negative
Anti-HBc IgM
Negative
ALT
18 U/L (normal)
1️⃣ Diagnosis: (Write your answer below)
2️⃣ Any other test: (Write your answer below)
3️⃣ What to do next: (Write your answer below)
4️⃣ Follow-up plan: (Write your answer below)
✅ Model Answer:
• Diagnosis: Previous HBV vaccination with low anti-HBs level (<10 mIU/mL) – not protective.
• Any other test: No additional testing needed; repeat anti-HBs if booster given.
• What to do next: Administer a booster dose of hepatitis B vaccine (single dose).
• Follow-up plan: Re-check anti-HBs 1-2 months after booster. If anti-HBs >10 mIU/mL → immunity achieved. If remains <10, complete additional 3-dose series and re-test.
Case 5
A newborn born to an HBsAg-positive mother. Received HBIG and first vaccine at birth. Now 9 months old.
HBsAg
Negative
Anti-HBs
95 mIU/mL (elevated, >10)
Anti-HBc Total
Negative
Anti-HBc IgM
Negative
ALT
22 U/L (normal)
1️⃣ Diagnosis: (Write your answer below)
2️⃣ Any other test: (Write your answer below)
3️⃣ What to do next: (Write your answer below)
4️⃣ Follow-up plan: (Write your answer below)
✅ Model Answer:
• Diagnosis: Successful HBV prophylaxis – HBsAg negative, anti-HBs positive (>10 mIU/mL), anti-HBc negative (no infection).
• Any other test: None needed; confirms protection.
• What to do next: No further intervention; child is protected against HBV.
• Follow-up plan: No routine follow-up needed. Maintain routine vaccination schedule. If immunocompromised later, check anti-HBs and consider booster.
Case 6
A 16-year-old with resolved hepatitis B infection (past infection). Anti-HBc positive, anti-HBs positive.
HBsAg
Negative
Anti-HBs
45 mIU/mL (positive)
Anti-HBc Total
Positive
Anti-HBc IgM
Negative
HBeAg
Negative
Anti-HBe
Positive
HBV DNA
Undetectable
ALT
20 U/L (normal)
1️⃣ Diagnosis: (Write your answer below)
2️⃣ Any other test: (Write your answer below)
3️⃣ What to do next: (Write your answer below)
4️⃣ Follow-up plan: (Write your answer below)
✅ Model Answer:
• Diagnosis: Resolved hepatitis B infection (immunity) – HBsAg negative, anti-HBs positive, anti-HBc positive, HBV DNA undetectable.
• Any other test: No further testing needed unless immunosuppression is planned (then check HBsAg and HBV DNA).
• What to do next: Reassure; the patient is immune. No vaccination needed (naturally acquired immunity).
• Follow-up plan: No routine monitoring. However, if patient undergoes immunosuppressive therapy (chemotherapy, transplantation), monitor for reactivation (check HBsAg, HBV DNA, ALT). Consider antiviral prophylaxis.
Case 7
A 14-year-old with chronic hepatitis B on tenofovir for 3 years. HBV DNA undetectable, ALT normal. Wants to stop medication.
HBsAg
Positive
Anti-HBs
Negative
Anti-HBc Total
Positive
HBeAg
Negative
Anti-HBe
Positive
HBV DNA
Undetectable
ALT
22 U/L (normal)
1️⃣ Diagnosis: (Write your answer below)
2️⃣ Any other test: (Write your answer below)
3️⃣ What to do next: (Write your answer below)
4️⃣ Follow-up plan: (Write your answer below)
✅ Model Answer:
• Diagnosis: Chronic hepatitis B with virologic suppression on tenofovir – HBeAg negative, undetectable HBV DNA, normal ALT.
• Any other test: Quantitative HBsAg (may help predict seroclearance), liver stiffness measurement (FibroScan), renal function and bone density.
• What to do next: Advise against stopping therapy. Tenofovir is suppressive, not curative. HBsAg seroclearance (loss) is the only cure, but rare. Stopping risks viral rebound and hepatitis flare.
• Follow-up plan: Continue tenofovir indefinitely. Monitor ALT, HBV DNA, renal function, and bone density every 6-12 months. If HBsAg becomes negative, consider stopping (after confirmation). HCC surveillance if cirrhotic.
Case 8
A 2-month-old infant of an HBsAg-positive mother. The mother has high viral load (HBV DNA >200,000 IU/mL) in third trimester.
Maternal HBsAg
Positive
Maternal HBeAg
Positive
Maternal HBV DNA
8,000,000 IU/mL
Infant HBsAg (at 2 months)
Positive
Infant Anti-HBs
Negative
Infant Anti-HBc Total
Positive
Infant ALT
45 U/L (normal for age)
1️⃣ Diagnosis: (Write your answer below)
2️⃣ Any other test: (Write your answer below)
3️⃣ What to do next: (Write your answer below)
4️⃣ Follow-up plan: (Write your answer below)
✅ Model Answer:
• Diagnosis: Perinatal HBV transmission – infant HBsAg positive despite prophylaxis, maternal high viral load.
• Any other test: Infant HBV DNA (viral load), liver function tests (INR, albumin), renal function. Check maternal viral load and HBeAg status.
• What to do next: Start infant on antiviral therapy (tenofovir or entecavir once age ≥2 years; options limited for <2 years). Refer to pediatric hepatology. Consider immunomodulation if chronic.
• Follow-up plan: Monitor infant HBV DNA, ALT, growth, and liver function regularly. Lifelong monitoring and treatment. Screen for cirrhosis and HCC in adulthood. Counsel mother about future pregnancies (maternal antivirals in third trimester).